Method for levelling the decks of ships

ABSTRACT

A method and apparatus for levelling buckled deck plates on ships. A wheeled carriage is motor driven across a deck plate and carries a transverse arm on which blowpipes for heating the plate are disposed. Atomizer nozzles are disposed on the arm between and behind the blowpipes. Cam controlled means are provided for axially shifting the arm at predetermined intervals whereby the linear areas heated by the blowpipes are thereafter rapidly cooled by the atomizer sprays to shrink the plate and restore a level surface.

[ Oct. 30, 1973 METHOD FOR LEVELLING THE DECKS 0F SHIPS Inventors:Jacques J. Godin, Triel-Sur-Seine;

Jacques A. Stephan, Nantes, both of France Assignee: Societe AnonyrnePour LEtude et LExploitation Des Procedes Georges Claude Filed: July 21,1972 Appl. No.: 273,907

Related US. Application Data Continuation of Ser. No. 883,720, Dec. 10,1969, abandoned.

Foreign Application Priority Data Dec. 20, 1968 France 68179430 US. Cl148/130, 148/127, 148/151,

148/152 Int. Cl C2ld l/52 Field of Search 148/130, 127, 151,

[56] References Cited UNITED STATES PATENTS 3,445,097 5/1969 Quinn[48/130 2,429,320 10/1947 Kennedy 148/130 Primary Examiner-Richard 0.Dean Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT Amethod and apparatus for levelling buckled deck plates on ships. Awheeled carriage is motor driven across a deck plate and carries atransverse arm on which blowpipes for heating the plate are disposed.Atomizer nozzles are disposed on the arm between and behind theblowpipes. Cam controlled means are provided for axially shifting thearm at predetermined intervals whereby the linear areas heated by theblowpipes are thereafter rapidly cooled by the atomizer sprays to shrinkthe plate and restore a level surface.

4 Claims, 2 Drawing Figures PATENTEDUBT 30 1325 3,769,102

METHOD FOR LEVELLTNG THE DECKS F SHIPS This is a continuation ofapplication, Ser. No. 883,720, filed Dec. 10, 1969, now abandoned.

This invention concerns a method of levelling the decks of ships andother large surfaces of metal sheeting by a succession of heating andcooling processes, as also an apparatus for carrying out the saidmethod.

It is known that the modern method of constructing ships usesconstruction techniques involving the welding of metal plates. However,despite precautions that have been taken, it must be admitted that theplates become deformed. Thus, the secondary decks, principally insuperstructures, tend, after welding to the side and, particularly asthe loading of the ship increases in the course of its armement, tobecome deformed. The deck then presents waves or pockets of metalbetween stiffening members, frequently amounting to rises of 20 30 mmbetween frames.

The conventional method of levelling consists in shrinking the excessmetal so as to return the initial rise to admissible values, that is tosay, 4 7 mm between the frames. This result is obtained by the hotshrinkage method, consisting in heating the plate locally to about 900C,then suddenly chilling it.

A series of successive local heating operations of 8-10 cm in lengththen follow, with a spaced interval of cm between them, parallel to thedeck stiffening members, commencing at 10 cm therefrom, starting fromthe axis of the ship towards the side and progressively approaching thefollowing stiffener. The heating operations are spaced quincuncially,that is to say, four at the corners and one in the middle, in order toavoid cracking or fracture of the plate.

Since the hatch from which one is operating is bordered on all sides bywelding seams connecting it to the hull, partitions and other areas ofdeck, the shrinkage results in subjecting to tension the platesconstituting the deck assembly, with the effect of stretching them and,consequently, reducing deformations in the forms of waves or pockets.

These operations are long and difficult, owing to the necessary labourinvolved and do not give a result equal to that which might be expectedtheoretically.

The method of the present invention makes it possible .to achieve aconsiderable reduction of deformations, no longer by only treating thedeformed parts until the existing rises disappear which in the end areonly partially reduced, but by proceding with rapid heat shrinkageoperations effectd simultaneously over a large area.

The method of the present invention is characterised by the featurethat, in the course of an initial phase, an assembly of areas is treatedsimultaneously by heating operations between 850 and 950 simultaneously,the said heating operations being followed by a sudden chillingoperation taking place within a time lapse of only a few seconds. Thisinitial phase may be followed, after a resting phase of l 3 hours, by athird phase, identical to the first, when the deforming rise is morethan mm.

Such a method cannot be effected manually, even with labour trained tocarry out levelling operations by heat treatments. Indeed, it is knownthat, in order to be efficient, the heating treatments must be fairlyclose together, with a spacing of the order of about 10 cm and bedisposed quincuncially in such manner as to avoid cracking or fracturingthe metal plate. The result is that such operations can not be carriedout simultaneously by workmen normally provided with only one blowpipe.Furthermore, despite their skill, the workmen cannot achieve the rapidchilling required by the method of the present invention which must takeplace a few seconds at the most after the plate has reached atemperature betwen 850 and 950.

Another object of the invention therefore resides in an automaticlevelling apparatus characterised in that it comprises a frame, asupport mounted on the frame, an assembly of blowpipes and wateratomisers mounted on the said support, tubes to feed the blowpipes andatomisers, and also a motor and wheels mounted on the frame for movingthe apparatus over the plates.

Such an apparatus makes it possible both to obtain an assembly ofsimultaneous heating operations and sudden chilling operations followingthe heating operations with any desired short interval of time.

Another object of the present invention concerns an apparatus of thistype in which the support of the blowpipes and atomisers is displaceablein a direction perpendicular to the displacement of the apparatus, a camturning synchronously with the displacement of the apparatus to controlat regular intervals the displacement of the said support in onedirection, then its displacement after a further interval in theopposite direction.

The advantage of such a device is that the length of the heatingoperations can be limited to 10 cm so as to avoid the effect of crackingdue to very long heating operations in a straight line, whilst avoidingthe extinction and re-lighting of the blowpipes.

For this purpose, the lateral displacement is effected very rapidly sothat the portion of the plate swept over in this movement is heated onlyto a negligible extent and so that the end of the transverse movement,the blowpipes recommence heating operations of 10 cm locatedquincuncially relatively to the preceding operations in lines parallelto the displacement of the apparatus.

In order that the invention may be readily carried into practice, oneembodiment will now be described in detail, by way of example, withreference to the accompanying drawings, in which:

FIG.1 is a perspective schematic view of the embodiment, selected by wayof example, of the apparatus of the present invention;

FIG.2 is a basic diagram showing the operation of the controls of theapparatus.

With reference to FIG.1, the frame of the apparatus, the side portionsand the cover of which are assumed to be partially broken away, supportsa motor 1, driving wheels 2 actuated by the said motor 1, loose wheels 3and two supports 4 and 5, the upper ends 6 and 7 of which comprise ineach case a roller on which a bar 8 rests. Pivoted on said bar, aboutaxes 9 and 10, are disposed two arms 11 and 12 resting on the plates tobe levelled by rollers 13, 14 pivoting about a vertical axis mountednear the end of supports 15 and 16 fixed to the arms. This particulararrangement enables the arms 11 and 12 to be kept at a given level abovethe surface, whatever the deformations of the plates may be between therollers 13 and 14 and, consequently, to keep the flames of the blowpipes17, 18, 19 and 20 carried by the arms, at a given distance from theplates. The adjustment of this distance is effected by sliding supports21 24 of the blowpipes.

Ducts such as and 26 feed the combustion supporting gasses and fuels toeach blowpipe. They are connected to a distributor 27 receiving thesefluids through two ducts 28 and 29.

A duct 30 supplies cooling water to secondary ducts 3]; and 32 feedingatomisers 33 and 34 located behind the arms ll and T2.

The distance between the alignment of blowpipes and the alignment ofatomisers is of the same order of magnitude as the length of the portionof the plate of sheet metal heated before passing to the followingposition; this distance may be different from this length. The atomisersmay be of any type and, in particular, comprise a compressed air jet soas to spread a veritable mist over the area concerned. Continuousefficient cooling may thus be readily obtained as soon as desired afterthe ceasing of the heating process.

A cam 35, driven by the motor I, actuates by way of a roller 36 a pivotvalve 39 controlling, through the intermediary of a piloted valve 41,the lateral displacement of the bar 8.

In the embodiment concerned, as driving motor, a compressed air motorhas been selected, shown schematically in FIG. 2 by the rectangle 1.This motor is fed by a pneumatic feeding unit 37 and causes the rotationof the cam by a device indicated schematically by the dotted line 38. Inthe course of its rotation the cam 35 actuates, by way of the member 36,the pilot gate valve 39 controlling the reversal of a double-action jack40 through the intermediary of the piloted valve 41. The members 42 and43 are conventional feed regulators and may be of any desired type. Thesame applies to the gate valves 39 and 411.

When the cam 35 actuates the valve 39, the latter controls the pilotedvalve 41, which has the effect, in the condition shown, of urging thepiston 44 to the right. The piston rod 45 is also shown in FIG. I. Theend of this rod drives an extension arm 46 fixed to the bar 8.

It is obvious that this device could be quite easily replaced by anequivalent device. In particular, if an electric motor was substitutedfor the compressed air motor electro-valves could be employed and thecontrol for reversing the movement of the valve 8 could still beobtained at regular intervals.

The above-described operation controlled by the valve 41 has the effectof rapidly returning the blowpipes 17 20 to the right side of FIG. 2 inorder to effect four simultaneous heat treatments over a length of about10 cm, for example; another control by the cam 35 causes the blowpipesto move rapidly to the left, into the position shown in FIG. 1 as soonas the preceding simultaneous heat treatments are completed.

On the assumption that the blowpipes are spaced apart from each other by20 cm, the cam displaces the bar 8 by 10 cm in one direction, then inthe other. If the movement of the frame of the apparatus is 10 cmbetween two successive displacements of the bar, the traces of theimpacts of the flames of the blowpipes on the deck are disposed in twoseries of four lines, the traces in the same line being 10 cm long andseparated by an unheated space of 10 cm in one series, the foursimultaneous impacts are on the same line perpendicular to the path ofthe apparatus, in the other series they are at the level of the unheatedspaces of the first series of lines. The width of each of the traces isof the order of a centimetre, whilst the width of the mist issuing fromthe atomisers such as 33, 34 is of the order of a decimetre.

Although only one embodiment of the invention has been described, it isobvious that the number of blowpipes and water atomisers could bereduced or increased without departing from the scope of the presentinvention, that the atomisers could be disposed on a support rigidlysecured to the frame, or that circuits for controlling the gases on theblowpipes could be provided or again that the support of the blowpipecould be mounted at the front or rear of the general chasis of theapparatus.

What we claim is:

l. A method of levelling a deformed metal surface which may consist ofwelded metal plates, positioned on top of and supported by rigid supportmembers, comprising the steps of:

providing at least two heat sources for heating the metal surface;maintaining the heat sources at a predetermined distance from the metalsurface;

heating the metal surface to a temperature between 850C and 950C; movingthe heat sources in a first direction along the longitudinal axis of therigid plate support members over the metal surface parallel to eachother, whereby equal numbers of elemental surfaces are heated to atemperature between 850C and 950C; rapidly moving the heat sources in asecond direction perpendicular to the first direction of movement of theheat sources;

continuing movement of the heat sources in the first direction,

rapidly moving the heat sources in a direction opposite to said seconddirection following a predetermined distance of movement in said firstdirection, the combination of movements of said heating sources in saidfirst and second directions and the reversing of movement in said seconddirection creating a resulting quincuncial heating pattern on the metalsurface; and

cooling the elemental surface heated between movement in the seconddirection and following reversed movement by a liquid spray apredetermined time period after heating said elemental surface, wherebyformation of cracks is avoided during the leveling operation.

2. The method according to claim 1, wherein the heat sources aremaintained along paths spaced substantially 20 cm apart.

3. The method according to claim 1, wherein the direction of movement insaid second direction is reversed every l0 cm of movement of said heatsource in said first direction.

4. The method according to claim 1, wherein the distance of movement ofthe heat sources in said second direction is equal to one half thedistance between adjacent heat sources.

UNTTEE STATES PATENT oEETcE @ETRHMCATE @F CQRRECTIQN Patent No. 3 769102 Dated October 30 1973 Inventofls) Jacques J. GODIN et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Assignees name incomplete. Should read LAir Liquide, Societe AnonymePour LEtude ec L'Exploitation des Procedes Georges Claude Column 3, line19 Before "valve" delete "pivot" and substitute pilot Signed and sealedthis 9th day of April 1971;.

(SEAL) Attest:

EDWARD I' IQFLETCHEmJRT o. MARSHALL DANN Attestin-g OfficerCommissioner, of Patents FORM P0-105O (10-69) USCOMM-DC 60376-P69 U.S.GOVERNMENT PRINTING OFFICE 1969 0--3G6334.q

, UNITED STATES PATENT OFFICE CERTIFIQATE OF COECTION Patent No.3,769,102 Dated October 30, 1973 Inventofls) Jacques J. GODIN et a1 Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Assignees name incomplete. Should read L'Air Liquide, Societe AnonymePour LEtude et L'Exploitation des Procedes Georges Claude Column 3, line19 Before valve" delete pivot and substitute pilot Signed and sealedthis 9th day of April 197A.

(SEAL) Attest:

EDWARD I' LFLETCH'ERJR. C -I-'IARSHALL DANN Attestin-g OfficerCommissioner of Patents FORM USCOMM-DC 60376-P69 USv GOVERNMENT PRINTINGOFFICE 2 I969 0-356-334. q

2. The method according to claim 1, wherein the heat sources aremaintained along paths spaced substantially 20 cm apart.
 3. The methodaccording to claim 1, wherein the direction of movement in said seconddirection is reversed every 10 cm of movement of said heat source insaid first direction.
 4. The method according to claim 1, wherein thedistance of movement of the heat sources in said second direction isequal to one half the distance between adjacent heat sources.